find-mmc-bypartlabel

#!/bin/sh
#
# Tool for finding mmc device node path based on it's part label.
#
# Copyright (C) 2015 Jolla Ltd.
# Contact: Kalle Jokiniemi <kalle.jokiniemi@jolla.com>
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; version 2
# of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

# Pass the partition label name as $1
if [ -z "$1" ]; then
	echo "$0: Error, no label name given!" > /dev/kmsg
	exit 1
fi

if [ ! -d /sys/class/block ]; then
	echo "$0: Error, please mount sysfs" > /dev/kmsg
	exit 1
fi

while [ ! -d /sys/class/block/mmcblk[01]p* ] && [ ! -d /sys/class/block/sda ] ; do
    echo "find-mmc-bypartlabel: Waiting for /sys/class/block/mmcblk[01]p*..." > /dev/kmsg
    i=$(( ${i:-0} + 1 ))
    sleep 0.5
    if [ $i -eq 10 ]; then
        echo "find-mmc-bypartlabel: Error: timeout waiting for /sys/class/block/mmcblk[01]p*" > /dev/kmsg
        exit 1
    fi
done
while [ ${i:-0} -le 50 ] ; do
	for mmc_sysfs in /sys/class/block/mmcblk[01]p*/ /sys/class/block/sda*/; do
		if grep -q -w PARTNAME="$1" "$mmc_sysfs"/uevent 2> /dev/null; then
			FIMAGE_DEV_NAME=$(echo $mmc_sysfs | cut -d "/" -f 5)
			echo "/dev/$FIMAGE_DEV_NAME"
			exit 0
		fi
	done
	sleep 0.1
    	i=$(( ${i:-0} + 1 ))
done

echo "$0: Error, could not find partition label \"$1\"" > /dev/kmsg
exit 1